Problem: $ { \left[\begin{array}{rrr}{-2} & {4} & {0} \\ {2} & {2} & {-1}\end{array}\right]-\left[\begin{array}{rrr}{3} & {-2} & {0} \\ {1} & {-1} & {-1}\end{array}\right] = {?} } $
Answer: To find the difference of two matrices, subtract the corresponding items between each matrix. ${\left[\begin{array}{rrr}{-2}-{3} & {4}-{-2} & {0}-{0} \\ {2}-{1} & {2}-{-1} & {-1}-{-1}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rrr}{-5} & {6} & {0} \\ {1} & {3} & {0}\end{array}\right]}$